Forging press

ABSTRACT

The press comprises a forging box and at least one horizontal press ram having a free end. Gripping means are mounted on said free end and spring-biased in a closing sense. A first tool assembly comprising a tool frame and a tool is held by said gripping means on said free end of said press ram. A rotatable magazine comprises a plurality of angularly spaced retaining clamps, which are spring-biased in a closing sense. A second tool assembly is retained by one of said retaining clamps. First and second releasing means are mounted on said forging box. The press ram is movable to a tool-changing position, in which said gripping means are adapted to be opened by the operation of said first releasing means. Said magazine is rotatable to any of a plurality of angular positions, in each of which one of said retaining clamps is adapted to be opened by said second releasing means and closely adjacent to and in register with said gripping means when said press ram is in said tool-changing position. Said first tool assembly can be transferred from said gripping means to one of said retaining clamps when said press ram is in said tool-changing position and said magazine is in one of said angular positions. Said second tool assembly can subsequently be transferred from another of said retaining clamps to said gripping means when said magazine has been rotated to another of said angular positions and said press ram is in said toolchanging position.

United States Patent Kralowetz et al.

[ Sept. 10, 1974 FORGING PRESS [75] Inventors: Bruno Kralowetz; Hubert Grill,

both of Steyr, Austria [73] Assignee: GFM Gesellschaft fur Fertigungstechnik und Maschinenbau Aktiengesellschaft, Steyn, Austria 1 [22] Filed: July 23, 1973 [211 App]. No.: 381,498

[30] Foreign Application Priority Data Aug. 8, 1972 Austria 6848/72 [52] US. Cl 72/462, 29/568, 72/446 [51] Int. Cl B21j 13/02 [58] Field of Search 72/462, 446, 447, 448, 72/455;'29/568 [56] References Cited UNITED STATES PATENTS 3,316,629 2/1967 Meyer 29/568 3,466,971 9/1969 Meyer 29/568 3,604,083 9/1971 Antonietto 29/568 3,762,036 10/1973 Goebel 29/568 3,779,122 12/1973 Sawvell 72/448 Primary Examiner-C. W. Lanham Assistant Examiner-Gene P. Crosby Attorney, Agent, or Firml(urt Kelman [57 ABSTRACT The press comprises a forging box and at least one horizontal press ram having a free end. Gripping means are mounted on said free end and spring-biased in a closing sense. A first tool assembly comprising a tool frame and a tool is held by said gripping means on said free end of said press ram. A rotatable magazine comprises a plurality of angularly spaced retaining clamps, which are spring-biased in a closing sense. A second tool assembly is retained by one of said retaining clamps. First and second releasing means are mounted on said forging box. The press ram is movable to a tool-changing position, in which said gripping means are adapted to be opened by the operation of said first releasing means. Said magazine is rotatable to any of a plurality of angular positions, in each of which one of said retaining clamps is adapted to be opened by said second releasing means and closely adjacent to and in register with said gripping means when said press ram is in said tool-changing position. Said first tool assembly can be transferred from said gripping means to one of said retaining clamps when said press ram is in said tool-changing position and said magazine is in one of said angular positions. Said second tool assembly can subsequently be transferred from another of said retaining clamps to said gripping means when said magazine has been rotated to another of said angular positions and said press ram is in PAIENTEDSEP I man SHEET 2 0F 3 FORGING PRESS This invention relates to apparatus for changing the tools in forging presses which comprise preferably two horizontal press rams which carry the tools at their ends.

The development towards progressively faster and more efficient methods of production involves a need for a constantly increasing degree of automation. For this reason it has been attempted to minimize the strictly manual effort. In forging presses, the automatic control of the sequence of operations has been satisfactorily accomplished in most cases so that the actual forging program is performed by the machine automatically and virtually without human contribution. Only the change of tools has not yet been automated and must still be performed substantially by hand. Whereas the work is facilitated to some extent by handling means. lifting and supporting devices, the actual mounting of the various tools on the press rams must be performed by hand and has not been automated so far. For this reason, the change of tools is a highly complicated operation, which interrupts the cyclic operation of the machine because the forging press must be shut down for a relatively long time. Besides, additional labor is required although this is highly undesirable for an optimum economic utilization of the machine.

It is an object of the invention to eliminate these disadvantages and to provide an apparatus which in forging presses enables a fast and automatic change of the tools and which is simple in structure and reliable in operation as far as possible.

This object is essentially accomplished in that a rotatable magazine for holding a plurality of tools is associated with each press ram, the tools mounted in respective tool frames are adapted to be clamped to the press ram by gripping jaws and to be secured to the rotatable magazine by retaining clamps, and stationary pressure fluid-operated actuators or the like are secured to the forging box and provided with pressure-exerting rams and with expanding rams for automatically opening the gripping jaws and retaining clips, respectively, which are spring-loaded in a closing sense. This tool-changing apparatus can be used to change the tools on all press rams simultaneously without need for manual effort. The human activity involved is restricted to mere controlling and checking functions. As soon as the rotatable magazines have been filled with a predetermined set of tools, the machine is ready for its working program, which can now be fully automatically performed.

To enable a reliable clamping of the tools in position and to provide the same holding conditions for tools which differ greatly in shape, separate tool frames are provided, in which the tools are secured and which are secured to the press rams or in the magazines. When it is desired to use the forging press with a predetermined tool, the press rams are retracted and the magazines are rotated until the desired tools face the press rams. The tools are then secured to the press rams by the gripping jaws and the retaining clamps are opened to release the tools from the magazines. Because the jaws and clamps are spring-loaded in the closing sense, a secure fixation of the tools on the press rams and in the magazines is ensured and an undesired detaching of the tool is prevented. When the tools have been removed from the magazines, the latter remain in their instantaneous angular position. and the press rams are advanced and can begin the actual forging operation. When another change of tools is desired. the sequence of operations is performed in the reverse order so that the magazines receive the tools from the press rams in that the retaining clamps grip the tools and when the retaining clamps have snapped in on the tools the gripping jaws are opened to permit of a rotation of the rotatable magazines until the new tools are in position. The gripping jaws and retaining clamps are opened against spring force by pressure-exerting and expanding rams, respectively, which are operated by pressure fluid-operated actuators or the like. The actuators themselves are stationary and secured to the forging box so that movable conduits, couplings and the like are not required and the jaws or clamps can be opened only when the magazines and press rams are in predetermined positions. It will be understood that all operations performed by this changing apparatus are controlled by control means in such a manner that wrong operations need not be feared and, e.g., the gripping jaws can be opened only when the retaining clamps hold the tool in position, etc.

In a special embodiment of the invention, the rotatable magazines are rotatable about an axis which includes an angle of 45 with the associated press ram and have receiving brackets or the like, which protrude from the periphery of the magazines and carry the retaining clamps and form stops for the tool frames and extend also at an angle of 45 to that axis of rotation. The provision of the receiving brackets permits of an exact positioning of the tools which are mounted in the tool frames because the receiving brackets embrace the tool frames, which engage stops and can easily be held in this defined position by the retaining clamps. Owing to the inclination of the axis of rotation of the magazine relative to the axis of the press ram, and the inclination of the receiving brackets relative to the axis of rotation of the magazines, the machine may be built with a low overall height because the rotatable magazines do not excessively protrude upwardly. This arrangement ensures also that during each revolution of the magazine the receiving brackets are once at right angles and once parallel to the axis of the press ram. When the receiving brackets are horizontal and parallel to the press rams, the tools can be introduced into the magazines in a very simple manner because it is sufficient to lower the tools from above between the'brackets by a crane or the like and the tools can be immediately moved to the correct position for the retaining clamps. It will be understood that for a tool change the receiving brackets are at right angles to the axis of the press rams so that the tool frame and the tool are in a plane that is normal to the press ram.

In accordance with the invention, each press ram is provided with a backing plate, which serves to carry the tool and on which the gripping jaws are mounted. When the tools have been received from the magazine, they are firmly clamped by the gripping jaws against the backing plate so that each tool is held exactly in the desired position at the end of the press ram. The backing plate is firmly but detachably connected to the press ram by necked-down screws so that the backing plate can be replaced in case of damage or when repairs are required whereas it is not necessary to knock down the entire machine in such case as would be required if the gripping jaws or tools were directly secured to the press rams.

An embodiment of the invention is shown diagrammatically and by way of example on the accompanying drawings, in which FIG. 1 is a side elevation showing a forging press provided with apparatus for changing the tools,

FIG. 2 is an end view showing a press ram together with a backing plate, a tool, a tool frame, and receiving brackets of the magazine, and

FIGS. 3 to 5 are sectional views taken on lines III- -III, lV-IV and VV, respectively, in FIG. 2.

The forging press 1 comprises two horizontal press rams 2, which strike one against thqother and at their ends carry tools 3. The press rams 2;-are mounted in a forging box 4. Ram-adjusting means 5 are provided to adjust the stroke position of the rams. The press rams 2 are driven by eccentric shafts, which can be uncoupled from the drive motor 7 by clutches 6. A brake 8 serves to brake the moving parts and to arrest the press rams at their rear dead center.

A rotatable magazine 9 is associated with each press ram 2 and can hold a plurality of tools 3 in receiving brackets 10. The axis of rotation of each rotatable magazine 9 is inclined by an angle of 45 to the axis of the associated ram. The receiving brackets 10 include an angle of 45 with the axis of rotation of the magazine. The tools 3 can either be gripped in position on the press ram 2 by gripping jaws 11 or be secured to the rotatable magazine 9 by retaining clamps 12. The gripping jaws 11 and the retaining clips 12 are biased in a closing sense by spring elements 13, 14 and can be opened only against this spring force. Pressure-exerting rams l5 serve to open the gripping jaws ll. Expanding rams 16 are provided to open the retaining clamps 12. The pressure-exerting and expanding rams are operated by stationary fluid press-operated actuators 17, 18, which are secured to the forging box 4. The retaining clamps 12 are mounted on the receiving brackets 10 of the rotatable magazines 9, and the gripping jaws 11 are pivoted to a backing plate 20, which is detachably connected to the respective press ram 2 by necked-down screws, not shown. The tool 3 is enclosed by a tool frame 21, which is either clamped by the gripping jaws ll against the backing plate 20 and the press ram 2 or is clamped by retaining clamps 12 on the receiving bracket 10 of the magazine 9. To locate the tool 3 or tool frame 21 exactly in position for being clamped, the receiving brackets 10 are provided with stops l9 and the backing plate 20 is provided with centering steps 22.

Because the axis of rotation of each rotatable magazine 9 is inclined by an angle of relative to the axis of the press ram, and the receiving brackets 10 are inclined by an angle of 45 relative to said axis of rotation, the tool-changing apparatus does not substantially increase the overall height of the entire forging press 1. Besides, the receiving brackets 10 can be moved to a position in which they are normal to the press rams and to a position in which they are parallel to the press rams. The tools 3 cannot be changed and cannot be clamped in position on the press rams 2 unless the tool frame 21 and the base of the tool 3 are parallel to the end face of the press ram and to the backing plate 20. This will be the case when the receiving brackets 10 are normal to the axis of the press ram. When the receiving brackets are horizontal, i.e., parallel to the press rams,

new tools can be inserted in a very simple manner into the receiving brackets. which are then easily accessible for cranes or the like. When the rotatable magazines 9 have been filled in this way, the magazines are rotated until the tools used first face the backing plates 20. It will be understood that the drive means are then disconnected because the clutches 6 are disengaged, and the press rams are held in their rearmost position by the brake 8. The press ram-adjusting means 5 are now operated to advance the press rams 2 and the backing plates 20 into engagement with the tool frames 21 and tools 3 so that the centering steps cause the tools to assume the correct positions whereas the gripping jaws 11 are held open by the pressure-exerting rams 15. When the pressure-exerting rams are retracted, the spring-loaded gripping jaws close automatically and clamp the tool frames and tools against the backing plates. When the tools-have been firmly connected to the press rams, the expanding rams 16 can be operated to open the retaining clamps 12 so that the tool frames 21 are released from the magazines. The press rams are now provided with the tools and ready for operation. During the forging work. the rotatable magazines remain in their position so that when the tools are to be changed again the magazines can immediately receive with the same receiving brackets as before the tools which are to be changed. For this purpose, the press rams are again braked at their rear dead centers and by the adjusting means the tools are then slowly moved into the receiving brackets until the tools have been guided by the stops to the correct position, in which they are engaged by the retaining clamps. The gripping jaws are now opened, the press rams are retracted, and the magazines which are now freely rotatable are rotated until the next tools face the backing plates and press rams.

The stationary pressure fluidoperated actuators for operating the pressure-exerting and expanding rams serving to open the gripping jaws and retaining clamps are secured to the forging box and for this reason need not follow any movement performed during the toolchanging or forging operation. For this reason, complicated telescopic conduits or the like are not required. Stationary conduits are sufficient and do not involve any problems.

The tool-changing apparatus according to the invention is fully automatically operated by control and checking means which are not described more fully and serve to coordinate the various movements performed in succession. The tool-changing operation itself does no longer require human force and may be performed under control of an operator.

What is claimed is:

l. A forging press, which comprises a forging box,

at least one horizontal press ram having a free end,

gripping means mounted on said free end and springbiased in a closing sense,

a first tool assembly comprising a tool frame and a tool and held by said gripping means on said free end of said press ram,

a rotatable magazine which comprises a plurality of angularly spaced retaining clamps, which are spring-biased in a closing sense,

a second tool assembly which is retained by one of said retaining clamps, and

first and second releasing means mounted on said forging box,

said press ram being movable to a tool-changing position, in which said gripping means are adapted to be opened by the operation of said first releasing means,

said magazine being rotatable to any of a plurality of angular positions, in each of which one of said retaining clamps is adapted to be opened by said second releasing means and closely adjacent to and in register with said gripping means when said press ram is in said tool-changing position,

whereby said first tool assembly can be transferred from said gripping means to one of said retaining clamps when said press ram is in said tool-changing position and said magazine is in one of said angular positions, and said second tool assembly can subsequently be transferred from another of said retaining clamps to said gripping means when said magazine has been rotated to another of said angular positions and said press ram is in said tool-changing position.

2. A forging press as set forth in claim 1, in which each of said first and second releasing means comprise a stationary, pressure fluid-operated actuator mounted on said forging box.

3. A forging press as set forth in claim 1, in which said first releasing means comprise a first ram which is engageable with said gripping means to open the same when said press ram is in said tool-changing position, and

said second releasing means comprise a second ram which is engageable with each of said retaining clamps to open the same when said magazine is in such an angular position that said clamp is closely adjacent to and in register with said gripping means when said press ram is in said tool-changing position.

4. A forging press as set forth in claim 1, which comprises an additional horizontal press ram having a free end,

additional gripping means mounted on said free end of said additional press ram and spring-biased in a closing sense,

an additional first tool assembly comprising a tool frame and a tool and held by said additional gripping means on said free end of said additional press ram,

an additional rotatable magazine which comprises a plurality of angularly spaced additional retaining clamps, which are spring-biased in a closing sense,

an additional second tool assembly which is retained by one of said additional retaining clamps, and

additional first and second releasing means mounted on said forging box,

said additional press ram being movable to a toolchanging position, in which said additional gripping means are adapted to be opened by the operation of said first releasing means,

said additional magazine being rotatable to any of a plurality of angular positions, in each of which one of said additional retaining clamps is adapted to be opened by said additional second releasing means and closely adjacent to and in register with said additional gripping means when said additional press ram is in its said tool-changing position,

whereby said additional first tool assembly can be transferred from said additional gripping means to one of said additional retaining clamps when said additional magazine is in one of its said angular positions, and said additional second tool assembly can subsequently be transferred from another of said additional retaining clamps to said additional gripping means when said additional magazine has been rotated to another of its said angular positions and said additional press ram is in its said toolchanging position.

5. A forging press as set forth in claim 1, in which said magazine is rotatable about an axis of rotation which includes an angle of 45 with the longitudinal axis of said press ram,

said magazine carries a plurality of receiving brackets which protrude from the periphery of said magazine and include an angle of 45 with said axis of rotation, and

each of said receiving brackets carries one of said retaining clamps and comprises a stop that is engageable by one of said tool frames.

6. A forging press as set forth in claim 1, in which said press ram carries at said free end a backing plate and said gripping means are carried by said backing plate and hold said tool assembly against said backing plate. 

1. A forging press, which comprises a forging box, at least one horizontal press ram having a free end, gripping means mounted on said free end and spring-biased in a closing sense, a first tool assembly comprising a tool frame and a tool and held by said gripping means on said free end of said press ram, a rotatable magazine which comprises a plurality of angularly spaced retaining clamps, which are spring-biased in a closing sense, a second tool assembly which is retained by one of said retaining clamps, and first and second releasing means mounted on said forging box, said press ram being movable to a tool-changing position, in which said gripping means are adapted to be opened by the operation of Said first releasing means, said magazine being rotatable to any of a plurality of angular positions, in each of which one of said retaining clamps is adapted to be opened by said second releasing means and closely adjacent to and in register with said gripping means when said press ram is in said tool-changing position, whereby said first tool assembly can be transferred from said gripping means to one of said retaining clamps when said press ram is in said tool-changing position and said magazine is in one of said angular positions, and said second tool assembly can subsequently be transferred from another of said retaining clamps to said gripping means when said magazine has been rotated to another of said angular positions and said press ram is in said tool-changing position.
 2. A forging press as set forth in claim 1, in which each of said first and second releasing means comprise a stationary, pressure fluid-operated actuator mounted on said forging box.
 3. A forging press as set forth in claim 1, in which said first releasing means comprise a first ram which is engageable with said gripping means to open the same when said press ram is in said tool-changing position, and said second releasing means comprise a second ram which is engageable with each of said retaining clamps to open the same when said magazine is in such an angular position that said clamp is closely adjacent to and in register with said gripping means when said press ram is in said tool-changing position.
 4. A forging press as set forth in claim 1, which comprises an additional horizontal press ram having a free end, additional gripping means mounted on said free end of said additional press ram and spring-biased in a closing sense, an additional first tool assembly comprising a tool frame and a tool and held by said additional gripping means on said free end of said additional press ram, an additional rotatable magazine which comprises a plurality of angularly spaced additional retaining clamps, which are spring-biased in a closing sense, an additional second tool assembly which is retained by one of said additional retaining clamps, and additional first and second releasing means mounted on said forging box, said additional press ram being movable to a tool-changing position, in which said additional gripping means are adapted to be opened by the operation of said first releasing means, said additional magazine being rotatable to any of a plurality of angular positions, in each of which one of said additional retaining clamps is adapted to be opened by said additional second releasing means and closely adjacent to and in register with said additional gripping means when said additional press ram is in its said tool-changing position, whereby said additional first tool assembly can be transferred from said additional gripping means to one of said additional retaining clamps when said additional magazine is in one of its said angular positions, and said additional second tool assembly can subsequently be transferred from another of said additional retaining clamps to said additional gripping means when said additional magazine has been rotated to another of its said angular positions and said additional press ram is in its said tool-changing position.
 5. A forging press as set forth in claim 1, in which said magazine is rotatable about an axis of rotation which includes an angle of 45* with the longitudinal axis of said press ram, said magazine carries a plurality of receiving brackets which protrude from the periphery of said magazine and include an angle of 45* with said axis of rotation, and each of said receiving brackets carries one of said retaining clamps and comprises a stop that is engageable by one of said tool frames.
 6. A forging press as set forth in claim 1, in which said press ram carries at said free end a backing plate and said gripping means are carried by saId backing plate and hold said tool assembly against said backing plate. 